Pulp-screening device



Nov. 6 1923. 1,472,934

. A.R.PAULL PULP SCREENING DEVICE Filed Nov. 1 1920 '3 Sheets-Sheet 2ATTORNEYS.

Nov. 6 1923. 1,472,34

A. PAULL PULP SCREENING DEVI CE ATTORNEY5.

Patented Nov, 6, 1923.

um'rao STATES ARVIN R. PAULL, OF UTICA, NEW YORK, ASSIGNOR OF ONE-THIRDA 1,412,934 PATENT orrlce.

T0 BENJ MIN J.

FISHER AND ONE-THIRD TO WILLIAM F. MGCANN, BOTH OF UTIGA, NEW YORK.

PULIP-SCREENING DEVICE.

Application filed November 1, 1920. Serial No. 420,95e.

To all whom it may conaern:v

Be it known that I, AnvrN R. PAULL, citizen of the United States,residin at Utica, in the county of Oneida and tate of New York, haveinvented new and useful Improvements in Pulp-Screening Devices, of whichthe following is a specification.

This invention relates to pulp-screening machines, and particularlytocertain improvements in machines of this character of the type wherein arotating cage, provided with peripheral screen plates, is .employed forscreening the pulp, such as is shown and described in Patent No. 1,149,-534, granted to Arvin R. Paull August 10, 1915. i i

One object of the present invention is to provide improved means foroperating the plunger plates cooperating with the screen plates to moreeffectively vibrate the same in order to insure: a proper flow of pulpthrough the screen plates.

Another object of the invention is to provide improved means formounting the plunger-plates, as well as to improve the construction ofthe plates and secure more efficient operation of the same.

Another object of the invention is to pro vide an improved device ofthis character wherein the rotatable cage is mounted concentric with thecylindrical casing to more efficiently convey the pulp in a circularpath along the inner surface of the casing,

as well as the provision of suitable means for supplyingv water to thepulp at proper intervals in its travel to insure thorough screening ofthe material. a

A furtherobject of the invention is to provide improved means forflushing the refuse from the. face of the screen after the completion ofthe screening operation, and to provide means for suitably sprayingwater upon the outer surface of the screen plates at proper intervals inthe operation of the mechanism.

capacity of the machine may be varied to better adapt the same for useunder varying conditions of service.

Referring to the drawings,-

-Fig. 1 is a side elevational view of the machine, certain of the partsbeing broken away along the line 1-1 of Fig. 2 to better illustrate theoperating mechanism and the relative position of the parts;

'Fig. 2 is an end elevational view of the machine, with a portion of theouter casing broken away to show the relative positions of the screenplates and plungers cooperating therewith;

Fig. 3 is a topplan view of a. portion of one of the screen plates;

Fig. 4 is a bottom plan view of a portion of one of the plungers;

Fig. 5 is a detail sectional view taken along the line 5-5 of Fig. 2;

Fig. 6 is a detail view of a portion of one of the end plates;

Fig. 7 is a detail view of a portion of one of'the end plates, showingthe manner of securing one of the longitudinal tie-bars thereto;

Fig. 8 is a detail View of a portion of one rality of legs 2 arranged inany suitable.

manner for properly supporting the casing and the mechanism carriedthereby. The casing is provided with an inlet passage which ispreferably located above the center line thereof and opens intothe'cylindrical wall of the casing in a direction tangential to thecircle defined by a transverse section thereof. The casing is alsoprovided with a manhole 4 located at the top thereof and providing meansfor obtaining access to the operating mechanism in the interior of thecasing.

The casing is provided with a pair of end plates 5 and 6 located atopposite ends thereof and extending upwardly and around the innersurface of the casing adjacent to the ends of the cylindrical casing asshown in Figs. 1 and 2 of the drawings. A portion of the upper half ofthe end plates is open adjacent the center of the casing to permit aview through the upperport-ion of the casing whereby the operation ofthe mechanism may be observed. The end plates are each provided withsemicircular bearings 7 and 8, respectively, the purpose of which willbe more fully described hereinafter, and each end plate has a closedlower portion which terminates substantially on a line, with the axis ofthe casing. An opening 9 is formed in the closed lower portion of theplate 5 through which the screened pulp may pass from the machinethrough a'suitable discharge pipe (not shown). The upper portions of theend plates 5 and 6 are of annular form, as shown in Figs. 1 and 2, andeach of the said plates fits closely within and is firmly secured to theends of the cylnn drical casing so as to form, in effect, a portion ofthe casing.

A cage 10, comprising enlarged central recessed end portions 11 and 12formed at opposite ends thereof and having a cylindrical sleeve 13connecting said recessed portions, is mounted for rotation in thesemicircular bearings 7 and 8, and semicircular straps 1 1 and 15cooperate with the semicircular bearings 7 and 8, respectively, to formbearings for the recessed end portions 11 and 12, respectively, of thecage. Radiating from the enlarged centrally-recessed end portions 11 and12 is a plurality of spider arms 16 and 17, respectively, which supportspiders 18 and 19 adjacent to the end portions of the cylindricalcasing. The spiders 18 and 19 are polygonal in form and are providedwith bosses 20 extending inwardly towards the center of the casing; andlongitudinallyextending tie-bars 21 extend between the spiders 18 and 19and are connected to the bosses 20 in any suitable manner, as by screws21, after the manner shown in Fig. 7 of the drawings. The cage thusconstituted is concentrically mounted in the casing l and is polygonalin cross-section, being provided with a plurality of radial passages 22the walls of which are formed by the inner faces of the spiders 18 and19 and the side faces of adjacent longitudinally-extending tie-bars 21,as will be seen upon reference to Fig. 2 of the drawings.

The spiders 18 and 19 are provided with outwardly-extending annularflanges 24 and 25, respectively, the flange 24 cooperating with asimilar flange 26 formed upon the end plate 5, and the flangecooperating in a similar manner with a corresponding flange 27 carriedby the end plate 6. It will be seen that these cooperating flanges arepositioned closely adjacent each other but separated slightly so as notto interfere with the rotation of the cage relative to the casing andthe end plates secured thereto. A strap 28, overlies the adjacent edgesof the cooperating flanges 241 and 26 and is preferably capable ofadjustment whereby it may be drawn sufficiently close against the outercircumferences of these flanges to prevent the pulp from leakingtherebetween. A similar strap 29 overlies the cooperating flanges 25 and27 and is capable of adjustment in a similar manner to permit it to beso tensioned against'the outer surfaces of the flanges as to preventleakage of the pulp therebetween.

A plurality of substantially rectangular screen plates 30 are eachsecured to the corresponding exterior polygonal faces of theoppositely-positioned spiders 18 and 19 and adjacent-longitudinally-extending tie-bars 21, whereby the outer surfaces of thecage 10 presents the appearance of a polygonal prism when the passages22 are covered by the screen plates 30. Each screen 30 is provided witha plurality of slots 31, the side walls of each slot being inclinedinwardly towards each other, whereby the slots are widened as theyextend towards the center 'of the cage to more effectively separate thefiner portions of the pulp from the coarse splinters, etc., as shown inFig. 2 of the drawings.

The longitudinallyextending tie-bars 21 are each'provided with inclinedouter faces 33 against which the screen plates 30 are adapted to-bearwhen they are positioned upon the adjacent tie-bars andoppositelylocated spiders, and the adjacent side edges of adjoiningscreen plates are secured in position by means of alongitudinally-extending angle-bar 34 provided withoppositely-projecting flanges 35 adapted to overlie the adjacent edgesof the adjoining screen plates and clamp them firmly against theinclined outer faces of the longitudinallyextending tie-bars. Each ofthe angle-bars .34 is secured to the corresponding tie-bar by means of arow of screws 36, or other suit able fastening means, positionedcentrally thereof and adapted to pass into the tie-bar to rigidly secureeach angle-bar toits corresponding tie-bar and firmly clamp the adjacentedges ofadjoining screen plates therebetween. Each of the angle-bars 34is provided with an outwardly-extending flange 37 extendingsubstantially throughout its length, and a radial fin 38' is suitablysecured in any desired manner to each flange 37 and extends outwardlyfrom the cage in a radial direction and into approximate engagement withthe inner surface of the casing witlr which it'is substantially incontact as the" cage rotates within the casing.

Located in each passageway 22 and radially inward from each screen plate30 is a plunger 40 substantially coextensive with the correspondinscreen plate 30 and adapted to be vibrate during rotation of the cage todraw the finer portion of the pulp through .in Figs. 1 and 2 of thedrawings, and has its outer edge projecting within grooves 42 formed inthe inner faces of the spiders 18 and 19 and grooves 43 formed in theside faces of the longitudinally-extending tiebars 21. The plungers arereciprocated towards and from the screen plates, but the distance whichthey move is relatively slight and is insufficient to entirely withdrawthe edges of the rubber strip from the grooves 42 and 43, thus a seal isprovided around the outer edge of each plunger so that theradial passage22 in which it moves is entirely closed by the plunger and a mostefficient suction effect produced upon the screen by reciprocation ofthe plunger.

Each plunger is provided with one or more openings 45 formed therein andpreferably located adjacent to the longitudinal center of the plunger.In the present in stance, these openings are three in number and areeach of oblong form as shown in Fig. 4. A slide 46, preferably formed ofa flexible metal and provided with parallel guide-slots 47, is securedto the inner surface of each plunger 40, where it is retained againstaccidental removal or displacement by bolts or rivets 48 carried by theplunger and passing through the parallel slots 47, the said bolts orrivets being provided with enlarged heads 49 which overlie a portion ofthe slide adjacent to the slots 47 and thus hold the slide againstaccidental removel from the plunger while permitting the same to bemoved longitudinally of the plunger to partially cover the openings 45,when desired. The slide is provided with an outturned handle 50 whichmay be grasp d for moving the slide longitudinally o the plunger toadjust the same in position over the opening 45, and a tooth 51is'provided upon the under surface of the slide 46 for engagement withany one of a plurality of notches 52 formed in the under surface of theplunger 40, whereby the slide may be held in any one of a plurality ofadjusted positions in which the openings 45 are closed to any desiredextent. Each plunger is provided with a pair of longitudinally-extendingribs 54 and 55, which are connected together near the longitudinalcenter of the plunger by a bafile-plate 56 which extends transversely ofthe plunger and is spaced a slight distance therefrom, being locateddirectly opposite the openings 45 formed in the plunger Radial stems 58.each of which is provided with a flattened head 59, support oppositeends of each plunger, the fiattened'heads 59 being secured to theplunger by suitable fastening means 60. The stems 58 are slidablymounted in radial sleeves 61 carried by the oppositely-positionedrecessed end portions 11 and 12 of the cage, and leakage of pulp aroundthe stems is prevented by any suitable means, such as packing 62 andglands 63. Cam-followers 65 are threaded upon the inner ends of thestems 58, and suitable coiled springs 66 surround the inner ends of thestems 58 and bear against the cam-followers 65 and a portion of theinner surface of the recessed end portions 11 and 12 to normally urgethe stems 58 radially inward into retracted position.

A shaft 67 is rotatably mounted in the sleeve 13 forming a part of thecage 10 and is supported for rotation by bearings 68 carried by therecessed end portions of the cage. The shaft 67 is concentricallymounted relative -to both the casing and the cage. Cams 70 are rigidlysecured to the shaft 67 in posi tion to operatively engage the two setsof cam-followers 65 and actuate the same to force the stems 58 radiallyoutward against the tension of the coiled springs 66. Theoppositely-positioned cams ed as to actuate the stems 58 carried by eachplunger simultaneously and thus more both ends of each plunger inunison.

Suitable means is provided for rotating the cage 10 in the bearings 7and 8 and at the Same time rotating the shaft 67 for actuating the stems58 to vibrate the plungers 40 carried by the cage. The cage ispreferably rotated at a considerably lower speed than the shaft 67,Whereby the plungers 40 are each vibrated a considerable number oftimes (preferably from 100 to 200) during each complete revolution ofthe cage. Any suitable form of driving mechanism may be employed forrotating the shaft 67 ,such as the usual fast-and-loose pulleys (notshown), and the cage is preferably rotated from the shaft 67 through anysuitable form of reduction-gearing, such as that shown for the purposeof illustration in the accompanying drawings.

In the form of reduction-gearing illustrated herewith, a spur-gear 72 iskeyed or otherwise rigidly secured to the shaft 67 which meshes with aspur-gear 73 carried by a suitable counter-shaft rotatably supported bya. standard 74 and a bracket 75 secured to the casing. A bevel-gear 76is also fixedly secured to the counter-shaft and meshes with abevel-gear 77 secured to a shaft 78 rotat- 70 are so adjustably mountedin the bracket 75 and located substantially at right-angles to thecountershaft mentioned above. The shaft 78 is protively slow rotativemovement may be imparted to the cage. In this way, the cage, togetherwith the series of peripheral screen plates carried thereby and theseries of plungers cooperatingwith the screen plates, 'may be rotatedbodily, while at the same other through annular passages 84, and 85 atopposite ends of the casing. As the cage rotates in the direction of the-arrow A shown in Fig. 2 of the drawings, the fins forming the sidewalls of these open-ended compartments travel aroundthe interior of thecasing, thus tending to cause the greater portion of the pulp to travelin a circular path about the interior of the casing and be screened byhaving the finer portions thereof drawn through the peripheral screenplates carried by the cage through the continued vibration of theplungers. One or more pipes 86 may be provided to pass through the endplate 6 and communicate with the annular passage 85 for supplying waterto the pulp as it is forced around the casing so as to insure a properfluidity for'the pulp to enable it to be efficiently screened.Longitudinally-extending spray-pipes 87 and 88 extend along the uppersurface of the casing, each of which pipes is provided with a pluralityof downwardly-directed openings communicating with the interior of theeasing, whereby a spray of water may be delivered to the outer surfacesof the screen plates at proper points in their travel to add water tothe pulp deposited upon the screens and clear the openings in the screenplates of particles of pulp which may be lodged therein.

Located in the end plates 5 and 6 adjacent to the upper portion of thecasing and extending above the normal level of the pulp in the casingare inwardly-projecting partitions 90 and 91 arranged substantiallyflush with the ends of the radial fins 38, as shown in Fig. 1 of thedrawings, and extending a suflicient distance circumferentially of thecasing to substantially close the normally open end of each of thecompartments above mentioned during the latter portion of its travelaround the casing. The partition 91 is provided with an oblong opening93, as shown in dotted lines in Fig. 2, and directly opposite theopening 93 is a water-supply pipe 94 which passes 1 ,araesa through theend plate 6 and the partition-plate 90. When each. of theabove-mentioned open-ended compartments reaches this pointin theirtravel about the casing, practically all of the pulp originallycontained in the compartment has been screened and there remains uponthe outer surface of the screen a quantity of refuse'such-assplinters,coarse particles'of pulp, etc., which would not pass through the screen.A jet of water flowing through the pipe at flushes the surface of thescreen, thus cleaning th same and driving the accumulated refuse acrossthe face of the screen and through the opening 93 above described, fromwhence it passes downwardly through a passage 95 between the parti tion91 and the outer surface of the end plate and is discharged from thepassage through an opening 96, to which a pipe or other suitable meansmay be secured to convey the refuse away and discharge the same into adrain. The spray-pipe 88 serves to spray a slight amount of water overthe screen just prior to its again becoming immersed in the pulp andthus insure a clear screening surface during the working period of thescreen.

In order to vary the capacity of the machine and enable the same to bereadily adapted to needs of plants having different capacities, it isproposed to increase the capacity of the machine over that of thestandard form b increasing the diameters of the casing an cage to suchan extent as to make it possible to place additional screen plates uponthe periphery of the cage or to increase the length of the cage andcasing, or both increase the diameter and length of the cage and casingto give greater screening surface, as may be found necessary ordesirable. In increasing the diameter of the cage and consequentlyadding to the screening area, it is desirable to increase the number ofscreen plates by two or multiples of I two in order that an even numberof screen plates may always be carried by the cage.

The modification illustrated in Figs. 9 and 10 discloses one means whichmay be employed for arranging and supporting the screen plates upon thecage when the length of the cage is increased to give greater effectivescreening surface. In this arrangement of the cage mechanism the shaft67 is mounted concentrically with'the cage, as in the form previouslydescribed,and spiders 18 and 19 are employed for supporting the outerend portions of screen lates 100 and 101, which may be employed infieadof a continuous screen plate extending the entire length of the cage andhaving its ends supported by the spiders-18 and 19. A spider 102 ispreferably secured to the sleeve 105 midway between the end spiders 18and 19 and is provided with a plurality of radiating III arms 103, eachof which supports the central portion of one of thelongitudinally-extending tie-bars 104, which tie-bars are similar in allrespects to the tie-bars 21 previously described and serve to supportthe screen plates 100 and 101 in precisely the same manner as thetie-bars 21 support the screen plate 30. The outer ends of the arms 103are bolted or otherwise fixedly secured to the inner faces of thelongitudinally-extending tie-bars in any suitable manner, and plungers106 extend between the spiders 18 and '19, the side and end edges ofwhich are. connected to the side faces of the tiebars and end spiders bystrips 107 formed of rubber or other flexible material in the samemanner as illustrated above in connection with the structure shown inFigs. 1 and 2. Each of the plungers is provided with stems 108 securedto its inner surface at opposite ends thereof, which stems are adaptedto be actuated in the manner previously described for vibrating theplungers during the rotation of the cage. In fact. the structure shownin Figs. 9 and 10 is similar inall respects to that previouslydescribed, except that the lingitudina-lly-extending tie-bars as well as-the plungers are .made of considerably greater length in order tolengthen the cage the desired amount and the central spider 102 istherefore employed to provide an additional .support for the tie-bars.As stated, the screen plates may also be divided so that two screenplates are employed for covering each of the polygonal faces of thecage, the two screen plates thus employed having their meeting edgesarranged adjacent the spider 102, as shown in Fig. 9 of the drawings.

From the above description it will be seen that as the pulp enters thespace between the cylindrical casing and the exterior surface of thecage through the inlet 3, it is engaged by the fins mounted upon theouter surface of the cage and carried around the interior of the casingin the open-ended compartments above mentioned. During the progress ofthe pulp along the interior surface of the casing, the plungers areconstantly vibrated, whereby the finer portions .of the pulp are drawnthrough the screen plates into the radial passages 22 between the screenplates and plungers. from which it flows inwardly through the openings45 formed in the plungers into the interior of the cage. When the levelof the finer pulp in the interior of the cage rises above the level ofthe opening 9 formed in the coverplate 5. it flows therethrough into asuitable pipe or receptacle provided for the purpose.

Leakage of the unscreened pulp around the casing or into the interior ofthe cage is prevented by the straps 28 and 29 positioned over thecooperating flanges carried by the cage and casing, respectively. As thecage the outer through the spray pipes 87 and 88, and the continues torevolve, water is sprayed upon surfaces of the screen plates iefuse isflushed by discharge of water from pipe 94 from the surface of eachscreen plate into the opening 93, thus removing the coarser parts of thepulp before the screen plate again becomes immersed in the pulpcontained in the casing. The recessed end portions 11 and 12 are soformed as to permit of ready access to the cam-followers, whereby theymay be adjusted to give the requisite throw to the plungers. as well asto permit the coiled springs to be readily removed and replaced, ifnecessary.

While the present embodiment of the invention has been described withconsiderable particularity in order to make it clear to those skilledinthe art the precise details of construction which may be employed inits use, it is to be understood that the invention is not limited to theprecise details of construction shown and described, or any of them,except as they may be set forth in the following claims.

What I claim is+- 1. In a pulp-screening machine, a cylindrical casing,a cage concentrically mounted for rotation with a plurality ofperipheral screen plates, a reciprocable plunger cooperating with eachscreen plate, means for rotating the cage, and means for reciprocatingthe plung- 'ers during the rotation of said cage.

2. In a pulp-screening machine, a substantially cylindrical casing, a.cage concentrically mounted for rotation in said casing and providedwith a plurality. of peripheral screen plates, and a. plurality ofradial fins carried by said cage, and projecting outwardly therefrom andconstantly engaging the inner peripheral surface of the cylinder duringrotation of the cage.

3. In a pulp screening machine a substantially cylindrical casing. ascreening cage concentrically mounted for rotation in said casing, aplurality of radial fins carried by said cage and projecting outwardtherefrom and constantly engaging the inner periph oral surface of thecylinder during rotation of the. cage, an inlet for pulp opening intothe cylindrical wall of the casing and means for supplying additionalwater to the pulp in the chambers between adjacent fins as it moves in acircular path along the interior of the casing.

4. In a'pulp-screening machine, a substan tially cylindrical casing. anda screening cage concentrically mounted for rotation in said casing andprovided with radial fins mounted for substantial engagement with theinterior surface of the casing throughout its extent forconveying. thepulp therearound'.

5. In'a pulp-screening machine, a substaninsaid casing and providedtially cylindrical casing, a screening cage concentrically mounted forrotation in sa d casing and provided with radial fins mounted forsubstantial engagement with the nterior surface of the casing during theentire rotation of the cage and dividing the annular space between thecage and casing into a plurality of open-ended compartmentscommunicating with each other through annular passages provided at theends of the casin 6. n a pulp-screening machine, a substantiallycylindrical casing, a screening cage concentrically mounted for rotationin said casing and provided with radial fins mounted for substantialengagement with the interior surface of the casing during the entirerotation of the cage and dividing the annular space between the cage andeasing into a plurality of open-ended compartment-s communicating witheach other through annular passages provided at the ends of the casing,and means for exerting suction upon portions of the cage to screen pulptherethrough.

7. In a pulp-screening machine, a substantially cylindrical casing, anda cage concentrically mlounted for rotation in said casing and providedwith a plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage andmounted for substantial engagement with the interior surface ofthe-casing during the entire rotation of the cage and dividing theannular space between the cage and casing into a plurality of open-endedcompartments come municating with each other through annular passagesprovided at the ends of the casing.

8. In a pulp-screening machine, a. sub-a stantially cylindrical casing,a cage concentrically mounted for rotation in said,

casing and provided with a plurality of screen plates located in theperipherythereof and separated from each other by radial fins carried bysaid cage, said fins being mounted for substantial engagement with theinterior surface of the casing during the entire rotation of the cageand dividing the annular space between the cage and easing into aplurality of open-ended compartments communicating with each otherthrough annular passages provided at the ends of the casing, and meansfor exerting suction upon said screen plates to draw pulp here through.

9. In a pulp-screening machine, a substantiallycylindrical casing, acage concentrically mounted for rotation in said casing and providedwith a plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage, said finsbei mounted for substantial engagement with t e interior evaose surfaceof the casing during the entire r0- tation of the cage and dividing theannular space between the cage and easing into a plurality of open-endedcompartments communicating with each other through annular passagesprovided at the ends of the casing, and reciprocable plungerscooperating with each screen plate to exert suction thereon and drawpulp therethrough.

10. In a pulp-screening machine, a sub stantially cylindrical casing, acage concen-,

trically mounted for rotation in said casing and provided with a.plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage, said finsbeing mounted for substantial engagement with the interior surface ofthe casing duri the entire rotation of the cage and dividing the annularspace between the cage and easing into a plurality of open-endedcompartments communicating with each other through annular passagesprovided at the ends of the casing, means for isolating each compartmentduring a. portion of its travel, and means for flushing the screen platein each compartment during its period of isolation to remove refusetherefrom.

11. In a pulp-screening machine, a substantially cylindrical casing, ascreening cage concentrically mounted for rotation within the casing andprovided with a plurality of screen plates located in the peripherythereof, radial fins carried by the cage and mounted for substantialengagement with the inner surface of the casing throughout its extent,means carried by the casing and cooperating with the fins for isolatingeach screen plate during a portion of its movement, and means forflushing the screen plate when it is isolated from the remainingportion. of the casing 12. In a pulp-screening machine, a substantiallycylindrical casing, a shaft mounted for rotation within said casing incoincidence with the axis thereof, a cage rotatably mounted upon'saidshaft and provided with a plurality of screen plates mounted upon theperiphery thereof, a plurality of plungers carried by said cage andcooperating with said screen plagtes, cam means carried by said shaftadjacent the opposite ends of said cage, and means connecting said cammeans with the opposite ends of said plungers for simultaneously andintermittently vibrating the opposite ends of said respective plungers.

13. In -a pulp-screening machine, a cylindrical casing, a cage rotatablymounted in said casing and provided wlth a plurality of peripheralscreen plates, a plurality of plungers carried by said cage andcooperating with said screen plates, a shaft supported by said casingand provided with cam means outside the opposite ends of said cage andmeans operatively connecting the said cams to the opposite ends of eachplunger within the cage for vibrating the plungers during rotation ofsaid cage.

14. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing and provided with plates and longitudinal ribs for dividingthe peripheral surface of the cage into radially-extending passages, ascreen-plate secured to the cage over each of said passages, a plungermounted in each passage and having its edges connected with the sidewalls of the passages by substantially liquid-tight joints, and meansfor reciprocatmg said plungers.

15. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing and provided with a plurality of radial passages formed inthe periphery thereof and separated from each other bylongitudinally-extending ribs, a screen plate secured to the cage overeach of said passages, a plunger mounted for reciprocation in each ofsaid passages and a flexible member secured to the edge of each plungerand engaging slots formed in the walls of the corresponding passage.

16. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing, a plurality of screen plates carried by said cage, aplurality of plungers carried by said cage and cooperating with saidscreen plates, means carried by the cage adjacent the opposite endsthereof and operatively connected with the opposite ends of saidrespective plungers for reciprocating both ends of each plungersimultaneously and equally and a shaft rotatably supported by. saidcasing and provided with means adjacent the opposite ends thereof foractuating said plunger-operating means.

17. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing and provided with centrally and inwardly recessed endportions, a plurality of screen plates carried by said cage, a pluralityof plungers carried by said cage and cooperating with said screenplates, a shaft rotatably supported by said casing concentric with saidcage, means carried by the cage and located at opposite ends thereof foroperating said plungers, and means located within the recesses of theend portions and on the outer sides thereof for actuating theplunger-operating means upon rotation of said shaft.

18. In a pulp-screening machine, a screen plate, a plunger-platecooperating therewith and provided with an opening formed therein, andmeans for regulating the effective size of said opening.

19. In a pulp-screening machine, a screen plate, a plunger-platecooperating therewith and provided with an opening formed therein, and aslide carried by said plate and adjustable to vary the effective size ofsaid opening,

20. In a pulp-screening machine, a screen plate, a plunger cooperatingtherewith and provided with an opening, and a bafiie located adjacent tosaid opening and spaced therefrom.

21. In a pulp-screening machine, a screen plate, a plunger cooperatingwith said screen and provided with an opening formed therein, means forregulating the effective size of said opening, and a baifle locatedadjacent said opening and spaced therefrom.

22. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing, a series of screen plates carried by said cage, a series ofplungers cooperating with said screen plates 'and each provided with anopening formed therein, andmeans for sealing the edges of the plungersto insure proper cooperation of the plungers with the screens. 7

23,. In a pulp-screening machine, a casing, a cage rotatably mounted inthe casing and provided with a plurality of'screen plates, tie-barsextending longitudinally of the cage, and longitudinally-extendinganglebars extending in a direction substantially parallel to that of thetie-bars and adapted to be secured thereto to clamp adjacent edges ofthe screen plates against theouter faces ofthe tie-bars and hold them inposition thereagainst.

24. In a pulp-screening machine, a casing, a cage rotatably mountedtherein and provided with a plurality of screen-plates carried upon theouter surface thereof, and a plurality of angle-bars extendinglongitudinally of said cage and adapted to secure the adjacent edges ofthe screen plates thereto, each of said angle-bars being provided with afin projecting outwardly radially from the outer surface of the cage andinto substantial engagement with the inner surface of the casing. I

25. In a pulp-screening machine, a substantially cylindrical casing, acage concentrically mounted for rotation in said casing and providedwith a plurality of peripheral screen plates, a reciprocable plungercooperating with each screen plate. means for rotating the cage, meansfor reciprocating stantially cylindrical casing, a screening cageconcentrically. mounted for rotation in said casing and provided withradial fins mounted for substantial engw nent with the interior surfaceof the cash during the centrically mounted for rotation in said casingand provided with a plurality of screen plates located in the peripherythereof and separated from each other by radial fins carried by saidcage and mounted for substan tial engagement with the interior surfaceof the casing during the entire rotation of the cage.

28. In a pulp-screening machine, a substantially cylindrical casing, acage concentrically mounted" for rotation in said casing and providedwith a plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage, said finsbeing mounted for substantial engagement with the interior surface ofthe casing during the entire rotation of the cage and means for exertingsuction upon said screen plates to draw pulp therethrough.

29. In a pulp-screening machine, a substantially cylindrical casing, acage concentrically mounted for rotation in said casing and providedWith a plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage, said finsbeing mounted for substantial engagement with the interior surface ofthe casing during the entire evaeee rotation of the cage andreciprocable plungers cooperating with each screen plate to exertsuction thereon and draw pulp therethrough.

30. In a pulp-screening machine, a substantially cylindrical casing, acage concentrically mounted for rotation in said casing and providedwith a plurality of screen plates located in the periphery thereof andseparated from each other by radial fins carried by said cage, said finsbeing mounted for substantial engagement with the interior surface ofthe casing during the entire rotation of the cage, means for isolatingeach compartment during a portion of its travel, and means for flushingthe screen plate in each compartment during its period of isolation toremove refuse therefrom.

31. In a pulp-screening machine, a casing, a cage rotatably mounted insaid casing and provided with a plurality of radial passages formed inthe periphery thereof and separated from each other bylongitudinally-extending ribs, a screen plate secured to the cage overeach of said passages, a plunger mounted for reciprocation in each ofsaid passages and a flexible member secured to the edge of each plungerand engaging the walls of the corresponding passage by a substantiallyliquid-tight joint.

In testimony whereof I have aflixed my signature.

ARVIN R. PAULL.

